Nanowire arrays are seeing increasing use in a variety of applications. See, e.g., U.S. Published Patent Application No. 2009/256134. An exemplary silicon nanowire array might consist of a collection of silicon nanowires, on the rough order of 100 nm in diameter, on the rough order of one micrometer in height, and of approximately cylindrical or frustoconical shape. The axes of the nanowires run approximately parallel to each other. Each is attached at an end to a silicon substrate. This structure is exemplary: there is also interest in other types of nanowires, which may for example comprise materials other than silicon, have axes oriented at angles to each other, or be randomly arranged, and which may not be attached to a silicon substrate.
It is becoming common to produce nanowire arrays by various forms of metal-enhanced etching. Naturally, in order for metal-enhanced etching to be part of a production process, many specific parameters may need to be controlled so as to produce nanowire arrays having the characteristics required for particular applications with characteristics having a suitably limited variation from batch to batch.
There is a need for nanowire array production processes which are more controllable and allow for easier and more efficient production of nanowire arrays having specific characteristics desired in applications.